I agree. And thus the LO could have ruled this as "sandbagging" and just DQ'd him, would have been the right thing to do.
I think DQing the team not just the player would not be a bad move. I don't see any situation in which a player would hide from his team that he is not left handed or lie about the reason he was doing it. The only situation that I would let the team off the hook is if they did not know that player, he never told them he right handed and he just happened to want to play lefty for fun without the team knowing and they did not know he would switch at the end. I would think the chances of proving any of those to the league would be 0.